Disclosed herein are ultra-violet curable gellant inks for three-dimensional printing, digital fabrication, and rapid prototyping applications. Also described is a method for forming three-dimensional images and objects with the described ultra-violet curable gellant inks.
Analog manufacturing is moving towards, and is expected to one day be consumed, by digital manufacturing. This shift is customer driven and arises from a desire for more customized products, on-demand delivery, and other market factors that support the move towards a less expensive alternative to traditional manufacturing. Digital fabrication encompasses a range of technologies.
Current technologies for three-dimensional printing include stereolithography and rapid prototyping. While suitable for some purposes, these technologies each have their own limitations. Stereolithography is a costly process with machines often costing in excess of $250,000. The polymer materials employed are also extremely expensive, with a common stereolithography photopolymer costing about $800 per gallon. Rapid prototyping systems typically use a fused deposition method wherein molten acrylonitrile-butadiene-styrene (ABS) polymer is deposited. The extremely rapid solidification of the ABS manifests in ridges that form on the finished object. Post-printing treatment of the prototype (such as sanding or polishing) is required to render a smooth object.
The concept of “freezing” or phase-change has been described for three-dimensional printing using aqueous inks on a chilled (that is, sub-zero temperature) substrate. See D. Mager et al., “Phase Change Rapid Prototyping With Aqueous Inks,” NIP23 and Digital Fabrication 2007 Conference Proceedings, pages 908-911, which is hereby incorporated by reference herein. Ink jet fabrication using wax based materials has been described but is disadvantaged by the fact that the resulting primary structures are neither robust nor permanent.
Commonly assigned, co-pending U.S. patent application of Peter M. Kazmaier, Hadi K. Mahabadi, Paul F. Smith, Chris A. Wagner, Gabriel Iftime, and Tyler B. Norsten, Ser. No. 11/613,759, entitled “Tactile Security Feature for Document and Signature Authentication,” filed Dec. 20, 2006, which is hereby incorporated by reference herein in its entirety, describes, in embodiments, a system and method create an authentication mark on a recording medium by depositing marking material on a medium in an image area to create a marking material image and to create a marking material authentication image. A predetermined amount of additional marking material is further deposited upon the medium in the authentication image area to increase an amount of marking material associated with the marking material authentication image in the authentication image area. The fixed marking material associated with the authentication image area is a tactilely perceptible authentication mark wherein the fixed marking material associated with the authentication mark has a height, with respect to a surface of the medium, that is tactilely perceptible.
U.S. Pat. No. 6,644,763 describes a method for creating raised and special printing effects using ink jet technology. The method includes the steps of depositing a light curable photo-polymer material on the area selected for the printing effects, and curing the area. The amount of material to be deposited corresponds to the area selected for the printing effects and the height of the raised area relative to the medium on which the photo-polymer material is deposited. See the Abstract.
U.S. Pat. No. 5,627,578 describes a method and device for raised letter or graphics printing, by means of a sprayed wet ink deposition on a print substrate. Subsequent dispensing of thermographic powder thereon, with adherence of the powder only to the wet ink, followed by heating to a fixing temperature of the powder, results in the raised lettering or graphics. A standard portable ink jet printer of the bubble jet type, controlled, with graphics software control, by a personal computer, provides the requisite non-contacting ink deposition. The dispensing cartridges of the ink jet printer are provided with non-contact-drying ink formulations (with two or more separate colors, if desired) for the portion of graphics or printing which is to be in raised form. A thermographic powder dispenser and heating member is connected to the output of the ink jet printer, or integrated therewith for completion of the raised printing process. Raised and non-raised printing is also possible by use of separately dispensed drying and non-drying inks. See the Abstract.
Ink jet printing devices are known in the art. For example, ink jet printing devices are generally of two types: continuous stream and drop-on-demand. In continuous stream ink jet systems, ink is emitted in a continuous stream under pressure through at least one orifice or nozzle. The stream is perturbed, causing it to break up into droplets at a fixed distance from the orifice. At the break-up point, the droplets are charged in accordance with digital data signals and passed through an electrostatic field that adjusts the trajectory of each droplet in order to direct it to a gutter for recirculation or a specific location on a recording medium. In drop-on-demand systems, a droplet is expelled from an orifice directly to a position on a recording medium in accordance with digital data signals. A droplet is not formed or expelled unless it is to be placed on the recording medium. There are generally three types of drop-on-demand ink jet systems. One type of drop-on-demand system is a piezoelectric device that has as its major components an ink filled channel or passageway having a nozzle on one end and a piezoelectric transducer near the other end to produce pressure pulses. Another type of drop-on-demand system is known as acoustic ink printing. As is known, an acoustic beam exerts a radiation pressure against objects upon which it impinges. Thus, when an acoustic beam impinges on a free surface (that is, liquid/air interface) of a pool of liquid from beneath, the radiation pressure which it exerts against the surface of the pool may reach a sufficiently high level to release individual droplets of liquid from the pool, despite the restraining force of surface tension. Focusing the beam on or near the surface of the pool intensifies the radiation pressure it exerts for a given amount of input power. Still another type of drop-on-demand system is known as thermal ink jet, or bubble jet, and produces high velocity droplets. The major components of this type of drop-on-demand system are an ink filled channel having a nozzle on one end and a heat generating resistor near the nozzle. Printing signals representing digital information originate an electric current pulse in a resistive layer within each ink passageway near the orifice or nozzle, causing the ink vehicle (usually water) in the immediate vicinity to vaporize almost instantaneously and create a bubble. The ink at the orifice is forced out as a propelled droplet as the bubble expands.
In a typical design of a piezoelectric ink jet device, the image is applied by jetting appropriately colored inks during four to eighteen rotations (incremental movements) of a substrate, such as an image receiving member or intermediate transfer member, with respect to the ink jetting head. That is, there is a small translation of the print head with respect to the substrate in between each rotation. This approach simplifies the print head design, and the small movements ensure good droplet registration. At the jet operating temperature, droplets of liquid ink are ejected from the printing device. When the ink droplets contact the surface of the recording substrate, they quickly solidify to form a predetermined pattern of solidified ink drops.
Ink jet printing processes may employ inks that are solid at room temperature and liquid at elevated temperatures. Such inks may be referred to as solid inks, hot melt inks, phase change inks and the like. For example, U.S. Pat. No. 4,490,731, the disclosure of which is totally incorporated herein by reference, discloses an apparatus for dispensing solid ink for printing on a substrate such as paper. In thermal ink jet printing processes employing hot melt inks, the solid ink is melted by the heater in the printing apparatus and utilized (jetted) as a liquid in a manner similar to that of conventional thermal ink jet printing. Upon contact with the printing substrate, the molten ink solidifies rapidly, enabling the colorant to substantially remain on the surface of the substrate instead of being carried into the substrate (for example, paper) by capillary action, thereby enabling higher print density than is generally obtained with liquid inks. Advantages of a phase change ink in ink jet printing are thus elimination of potential spillage of the ink during handling, a wide range of print density and quality, minimal paper cockle or distortion, and enablement of indefinite periods of nonprinting without the danger of nozzle clogging, even without capping the nozzles.
The use of ink jet printers in forming raised printed images is also known, for example, as indicated in U.S. Pat. Nos. 6,644,763 and 5,627,578 above.
Commonly assigned, co-pending U.S. patent application of Gabriel Iftime et al, Ser. No. 11/683,011, entitled “Dual Printer for Regular and Raised Print,” filed Mar. 7, 2007, which is hereby incorporated by reference hereinabove in its entirety, describes a cost-effective ink jet printing device that is capable of forming both regular print images and raised print images.
In general, phase change inks (sometimes referred to as “hot melt inks”) are in the solid phase at ambient temperature, but exist in the liquid phase at the elevated operating temperature of an ink jet printing device. At the jet operating temperature, droplets of liquid ink are ejected from the printing device and, when the ink droplets contact the surface of the recording substrate, either directly or via an intermediate heated transfer belt or drum, they quickly solidify to form a predetermined pattern of solidified ink drops. Phase change inks have also been used in other printing technologies, such as gravure printing, as disclosed in, for example, U.S. Pat. No. 5,496,879 and German Patent Publications DE 4205636AL and DE 4205713AL, the disclosures of each of which are totally incorporated herein by reference.
Phase change inks for color printing typically comprise a phase change ink carrier composition which is combined with a phase change ink compatible colorant. In a specific embodiment, a series of colored phase change inks can be formed by combining ink carrier compositions with compatible subtractive primary colorants. The subtractive primary colored phase change inks can comprise four component dyes or pigments, namely, cyan, magenta, yellow and black, although the inks are not limited to these four colors. These subtractive primary colored inks can be formed by using a single dye or pigment or a mixture of dyes or pigments. For example, magenta can be obtained by using a mixture of Solvent Red Dyes or a composite black can be obtained by mixing several dyes. U.S. Pat. No. 4,889,560, U.S. Pat. No. 4,889,761, and U.S. Pat. No. 5,372,852, the disclosures of each of which are totally incorporated herein by reference, teach that the subtractive primary colorants employed can comprise dyes from the classes of Color Index (C.I.) Solvent Dyes, Disperse Dyes, modified Acid and Direct Dyes, and Basic Dyes. The colorants can also include pigments, as disclosed in, for example, U.S. Pat. No. 5,221,335, the disclosure of which is totally incorporated herein by reference. U.S. Pat. No. 5,621,022, the disclosure of which is totally incorporated herein by reference, discloses the use of a specific class of polymeric dyes in phase change ink compositions.
Phase change inks have also been used for applications such as postal marking, industrial marking, and labeling.
Phase change inks are desirable for ink jet printers because they remain in a solid phase at room temperature during shipping, long term storage, and the like. In addition, the problems associated with nozzle clogging as a result of ink evaporation with liquid ink jet inks are largely eliminated, thereby improving the reliability of the ink jet printing. Further, in phase change ink jet printers wherein the ink droplets are applied directly onto the final recording substrate (for example, paper, transparency material, and the like), the droplets solidify immediately upon contact with the substrate, so that migration of ink along the printing medium is prevented and dot quality is improved.
Radiation curable inks generally comprise at least one curable monomer, a colorant, and a radiation activated initiator, specifically a photoinitiator, that initiates polymerization of curable components of the ink, specifically of the curable monomer.
U.S. Pat. No. 7,279,587 of Peter G. Odell, Eniko Toma, and Jennifer L. Belelie, the disclosure of which is totally incorporated herein by reference, discloses photoinitiating compounds useful in curable phase change ink compositions. In embodiments, a compound of the formula

is disclosed wherein R1 is an alkylene, arylene, arylalkylene, or alkylarylene group, R2 and R2′ each, independently of the other, are alkylene, arylene, arylalkylene, or alkylarylene groups, R3 and R3′ each, independently of the other, are either (a) photoinitiating groups, or (b) groups which are alkyl, aryl, arylalkyl, or alkylaryl groups, provided that at least one of R3 and R3′ is a photoinitiating group, and X and X′ each, independently of the other, is an oxygen atom or a group of the formula —NR4—, wherein R4 is a hydrogen atom, an alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group.
U.S. Patent Publication 20070120910, Ser. No. 11/290,202, Published May 31, 2007, of Peter G. Odell, Eniko Toma, and Jennifer L. Belelie, entitled “Phase Change Inks Containing Photoinitiator With Phase Change Properties and Gellant Affinity,” which is hereby incorporated by reference herein in its entirety, describes, in embodiments, a phase change ink comprising a colorant, an initiator, and an ink vehicle, said ink vehicle comprising (a) at least one radically curable monomer compound, and (b) a compound of the formula

wherein R1 is an alkylene, arylene, arylalkylene, or alkylarylene group, R2 and R2′ each, independently of the other, are alkylene, arylene, arylalkylene, or alkylarylene groups, R3 and R3′ each, independently of the other, are either (a) photoinitiating groups, or (b) groups which are alkyl, aryl, arylalkyl, or alkylaryl groups, provided that at least one of R3 and R3′ is a photoinitiating group, and X and X′ each, independently of the other, is an oxygen atom or a group of the formula —NR4—, wherein R4 is a hydrogen atom, an alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group.
U.S. Pat. No. 7,279,587 of Jennifer L. Belelie, Adela Goredema, Peter G. Odell, and Eniko Toma entitled “Method for Preparing Curable Amide Gellant Compounds,” issued Aug. 21, 2007, which is hereby incorporated by reference herein in its entirety, describes, in embodiments, a process for preparing a compound of the formula

wherein R1 is an alkyl group having at least one ethylenic unsaturation, an arylalkyl group having at least one ethylenic unsaturation, or an alkylaryl group having at least one ethylenic unsaturation, R2 and R3 each, independently of the others, are alkylene groups, arylene groups, arylalkylene groups, or alkylarylene groups, and n is an integer representing the number of repeat amide units and is at least 1, said process comprising: (a) reacting a diacid of the formulaHOOC—R2—COOH
with a diamine of the formula

in the absence of a solvent while removing water from the reaction mixture to form an acid-terminated oligoamide intermediate; and (b) reacting the acid-terminated oligoamide intermediate with a monoalcohol of the formulaR1—OH
in the presence of a coupling agent and a catalyst to form the product.
U.S. Pat. No. 7,276,614 of Eniko Toma, Peter G. Odell, Adela Goredema, and Jennifer L. Belelie, entitled “Curable Amide Gellant Compounds,” issued Oct. 2, 2007, which is hereby incorporated by reference herein in its entirety, describes, in embodiments, a compound of the formula

wherein R1 and R1′ each, independently of the other, is an alkyl group having at least one ethylenic unsaturation, an arylalkyl group having at least one ethylenic unsaturation, or an alkylaryl group having at least one ethylenic unsaturation, R2, R2′, and R3 each, independently of the others, are alkylene groups, arylene groups, arylalkylene groups, or alkylarylene groups, and n is an integer representing the number of repeat amide units and is at least 1.
U.S. Patent Publication 20070123606, Ser. No. 11/290,121, Published May 31, 2007, of Eniko Toma, Jennifer L. Belelie, and Peter G. Odell entitled “Phase Change Inks Containing Curable Amide Gellant Compounds,” which is hereby incorporated by reference herein in its entirety, describes, in embodiments, a phase change ink comprising a colorant, an initiator, and a phase change ink carrier, said carrier comprising at least one radically curable monomer compound and a compound of the formula

wherein R1 and R1′ each, independently of the other, is an alkyl group having at least one ethylenic unsaturation, an arylalkyl group having at least one ethylenic unsaturation, or an alkylaryl group having at least one ethylenic unsaturation, R2, R2′, and R3 each, independently of the others, are alkylene groups, arylene groups, arylalkylene groups, or alkylarylene groups, and n is an integer representing the number of repeat amide units and is at least 1.
U.S. Pat. No. 7,271,284 of Eniko Toma, Adela Goredema, Jennifer L. Belelie, and Peter G. Odell entitled “Process for Making Curable Amide Gellant Compounds,” issued Sep. 18, 2007, which is hereby incorporated by reference herein in its entirety, describes, in embodiments, a process for preparing a compound of the formula

having substituents as defined therein.
The appropriate components and process aspects of the each of the foregoing U.S. Patents and Patent Publications may be selected for the present disclosure in embodiments thereof.
Digital fabrication or rapid prototyping using non-impact printing technology is beginning to impact a wide range of technical disciplines including biotechnology, combinatorial chemistry, electronics, displays, MEMS (microelectromechanical systems) devices, photovoltaics, and organic semiconductors. Currently available materials for ink jet based digital fabrication are suitable for their intended purposes. However a need remains for improved materials suitable for use in non-impact three dimensional printing including digital manufacturing and rapid prototyping applications. Further needed is a marking material for ink jet based three-dimensional printing, digital fabrication, and rapid prototyping applications providing a final object having improved robustness, a method providing ease, simplicity of use, flexibility and tunability (that is, adaptability for different applications).